Pyrophoric ignition injection system



June 2, 1964 L. c. DAGNE 3,135,092

PYROPHORIC IGNITION INJECTION SYSTEM Filed NOY. 17, 1961 v INVENTOR LOU/S one/v5 I BY i ATTORNEYS United States. Patent 3,135,092 PYROPHORIC IGNITION INJECTION SYSTEM Louis C. Dagne, Juno, Fla., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed Nov. 17, 1961, Ser. No. 153,246 1 Claim. (Cl. 60--39.48)

The present invention relates to an ignition system, and more particularly to a pyrophoric ignition system capable of high altitude reignition of jet engines after flameout.

The instant invention solves the serious problem of complete lack of power of a jet engine caused by flameout or blowout. Upon sensing a flameout an explosive valve is triggered which admits high pressure nitrogen to provide the force necessary to drive a piston forward through a chamber. Pyrophoric fuel contained in the chamber is forced out into the fuelline. From the fuel line the pyrophoric fuel is forced to the burner where it comes into contact with oxygen bearing atmosphere and ignites.

The nitrogen gas purges the remaining fuel and follows the pyrophoric fuel into the fuel line. After the pressure of the nitrogen gas has diminished to a point below the pressure of the jet fuel which is normally used this jet fuel closes the check valve initially opened by the high pressure nitrogen.

Accordingly, it is an object of the present invention to provide an ignition system for reigniting jet engines at high altitudes.

Another object is to provide a pyrophoric ignition system directly to jet fuel lines for ignition of-jet engines.

A further object of the invention is the provision of a compact reignition system which is economical to manu- ,vision of a compact pyrophoric reignition system having having readily separable a nitrogen chamber, an explosive valve, and a pyrophoric fuel chamber.

A still further object is to provide a readily separable pyrophoric reignition system for jet engines which is compact, is simple in operation, and is substantially reusable.

A yet further object of the present invention is the use of the main jet fuel lines for transport of pyrophoric fuel while maintaining the pyrophoric fuel substantially uncontaminated.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

The figure illustrates, in sections, the pyrophoric ignition system of the invention.

Referring now to the drawing, there is shown chamber 11 containing nitrogen gas, an explosive valve 12, a container 33 of pyrophoric fuel, an injection T 14, and a valve ball 37 therein.

When a flameout is sensed either electronically or visually the igniter circuit 26 ignites a charge of gun powder or similar explosive 24 in explosion chamber 23. Angularly spaced radial vanes 25 support chamber 20 while allowing passage of gas thereby. The high pressure caused by the explosion of charge 24 drives pointed member 16 forward to thereby burst the nitrogen container 11 at point 15. Travel of the pointed pin member 16 into the nitrogen container 11 is limited by inwardly extending arms 21. The pointed pin member 16 is returned after the pressure of the explosion dissipates by spring 17 which normally holds the pointed pin 16 in a retracted position.

3,135,092 Patented June 2, 1964 Nitrogen gas being inert w'th pyrophoric fuel fulfills this most important criterion of the gas to be employed in the container 11. Also employed with the container 11 and with the gas to be maintained in the container is a pressure indicator 22. Pressure indicator 22 is employed to indicate the state of pressurization during and after storage as well as before use.

Explosive valve ear stops 46 are firmly held in contact with the high pressure nitrogen container 11 by an annular spring seat which has threads upon its outer circumference for engagement to the nitrogen container 11. It should be understood that the explosive valve could be instrumentedin accordance with any of the methods commonly known in the art. An external pyrophoric fuel container 13 is connected to the nitrogen container 11 by an annular member 30 which fits over a radial flange of the pyrophoric container 13. The annular member 30 draws the externalpyrophoric container into airtight relationship with nitrogen container 11 by threadably engaging said last mentioned container. The nitrogen container 11 has an annular groove in which is disposed an annular seal 31 such as an O-ring for abutting the radial flange of the external pyrophoric container 13 thereby achieving an airtight seal. It should also be understood that the leads of igniter circuit 26 are suitably maintained in the nitrogen chamber by sealing means well known in the art. Thus, it is insured that the nitrogen gas will not escape, after release out the opening maintained in the gas chamber for the igniter circuit leads.

Within the external pyrophoric container 13 is a flexible internal pyrophoric fuel container 33 which has at one end thereof a scored disc portion 35. The internal pyrophoric container 33 may be produced from any flexible material such as rubber or plastic which is substantially impervious to either air or to the pyrophoric fuel. At the other end of the external pyrophoric container 33 is a semi-spherical piston 32 which has a sharp projection 34 and an exhaust 45 through piston 32 and projection 34. The piston 32 is maintained in contact with the rear of the flexible internal pyrophoric container 33 by a spring 28 seated at one end against the piston 32 and at the other end against the annular spring seat 27. The spring 28 acts to allow expansion and contraction of various comsures to build up in the pyrophoric fuel container 33 or allowing any looseness between parts. The flexible internal pyrophoric container 33 also has an inwardly extending projection 36 about the piston projection 34.

The injection T 14 is connected to the external pyrophoric container 13 by a pair of interlocking members 42 and 43. The annular connecting member 42 is threadably connected to the injection T 14 while the annular connecting member 43 is threadably connected to external threads on the external pyrophoric container 13. The injection T 14 has two arms adapted to receive an incoming main jet fuel line 40 and outgoing main jet fuel line 41. Within the injection T 14 is an annular member 44, which has a valve seat capable of receiving the ball 37 of a check valve.

During storage the entire ignition system remains intact with only the pressure indicator 22 in operation. In operation, when a flameout is sensed or when the ignition device of the invention is otherwise needed the explosive valve 12 is actuated through the ignition circuit 26. The explosive valve 12 ruptures the nitrogen gas chamber 11 at point 15 thereby releasing the highly pressurized nitrogen gas. Upon being released the nitrogen gas exerts its pressure upon the piston 32 thereby rupturing the internal pyrophoric container 33 at its scored disc 35. After rupture of the pyrophoric container 33 the piston continues to traverse the container thereby forcing the ball 37 into the main fuel line to position 38. In this Way the fuel line is closed and the pyrophoric fuel is allowed to pass out through the injection T 14 and fuel line 41 to the jet engine burner. When the spherical piston 32' has completed its travel the projecting point 34 of the piston shears the pyrophoric fuel container projection 36 thereby allowing the nitrogen to exhaust through the piston exhaust 45 and out the fuel line. When the pressure of the nitrogen gas has diminished to a point less than the pressure of the jet fuel in fuel line 40 the ball 37 will be forced back to its valve seat in member 44.

Pyrophoric fuel is generally accepted as a fuel which ignites upon contact with air. Some of the pyrophoric fuels or combination thereof which it is contemplated may accomplish the purposes of the instant invention are: boron triethyl, aluminum tripropyl silane, aluminum triethyl and aluminum trimethyl.

The operation of the instant invention offers innumerable advantages. It otfers a compact system which is quickly separable and capable of having its major com,- ponents separately stored thus increasing the safety factor in handling the system. It offers a highly compact system of simple construction and operation thereby offering the important advantage of being economical. The invention also offers the advantage of being automatically and instantaneously operable to ignite a jet engine. Ignition may be accomplished on the ground and reinjection may be accomplished at high altitudes or any other altitudes so long as sufiicient oxygen exists to react with the pyrophoric fuel. The invention is also substantially reusable with only the internal pyrophoric fuel container 33 and the nitrogen container 11 requiring re placement before being refilled and readied for reuse. Thus the pyrophoric fuel may be replaced in the fuel container 13 by merely inserting another already filled internal pyrophoric fuelcontainer 33. The principle of the invention could also be used with the afterburner of the jet engine as Well as with the burner and a plurality of reigniters may be employed for various purposes. Flameout may be sensed visually or electronically with either automatic or selective manual activation of the ignition system. Of high importance of the instant invention is the advantage that the ignition system is directly connected to the main jet fuel line thus eliminating the need for separate lines, pre-cooling, and the extensive purging normally required for fuel systems operating intermittently in a high temperature ambient environment. The instant invention therefore needs only a minimum of purging accomplished by the exhausted nitrogen gas thereby preventing oxidation and fouling due to oxidation. The instant invention also allows the pyrophoric fuel to not only employ the main jet fuel line but to do so in such a manner as not to become significantly contaminated by the jet fuel. Contamination of the pyrophoric fuel reduces its concentration upon contact with air and, therefore, reduces the probability of reiginition.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claim the invention may be practiced otherwise than is specifically described.

What is desired to be secured by Letters Patent of the United States is:

In a jet engine ignition system of the type having a container for a pyrophoric fuel, a conduit for supplying the pyrophoric fuel from said container to said engine for spontaneous combustion therein whereby normal operation of said engine may be initiated, a piston movably mounted in said container, a rupturable chamber for containing a pressurized gas adjacent said container and explosive means for rupturing said chamber whereby said gas impinges upon. said piston thereby forcing said fuel out of said container through said conduit and into said engine for ignitiontherein, the improvement comprising in combination, a flexible receptacle selected from the group of materials which are impervious to pyrophoric fuel and air such as rubber and plastic, and shaped to conform to the interior of said container for storing the pyrophoric fuel therein, said piston terminating in an apertured projection for puncturing said flexible receptacle as said projection protrudes into said conduit thereby permitting the pressurized gas to exhaust through said aperture and conduit thus purging. the system of pyrophoric fuel, whereby said receptacle filled with fuel may be economically and safely handled and loaded into said contia'ner andsaid receptacle may be easily removed from said container.

References Cited in the file of this patent UNITED STATES PATENTS 2,237,014 Stoehrer Apr. 1, 1941 2,924,359 Beremand Feb. 9, 1960 2,954,670 Helus et al. Oct. 4, 2960 2,959,007 Gregory et al. Nov. 8, 1960 3,077,078 Hamilton Feb. 12, 1963 

